The Role of Graphene in Flame Retardancy of Polymeric Materials: Recent Advances

Background: From its discovery, graphene has become a very fascinating nanomaterial, thanks to its structure that determines peculiar (and unique) mechanical, electrical and thermal properties. Thus, graphene has stimulated and is still motivating several researchers to widen its potentialities that are currently being exploited in different application sectors, comprising catalysis and energy, nanoelectronics, quantum physics and the design and manufacturing of advanced nanocomposite materials and biomaterials. Being a carbon source, already organized in a well-ordered morphology, graphene is nowadays starting to experience a different application, i.e. in the fire retardancy of polymers, foams and textiles, often in combination with other flame retardant additives or nanofillers, with which graphene can often act in a synergistic way. In fact, it is well reported in the scientific literature that graphene and its derivatives can play a key role either in slowing down the flame propagation or even in providing self-extinction to the thermoplastic or thermosetting matrices, where the nanofiller is incorporated in; furthermore, by exploiting surface engineered approaches, it is possible to design very effective flame retardant coatings on textile substrates. Objective: This paper aims at reviewing the current state-of-the-art about the use of graphene and its derivatives as efficient flame retardant additives for different polymeric materials, highlighting the current limitations/achievements and discussing some possible future developments. Keywords: Barrier properties, char, flame retardancy, graphene, graphene oxide, polymer nanocomposites, synergistic effects.